Long hyaline gland discharge and multiple spermatophore formation by the male grasshopper, Melanoplus sanguinipes

Abstract

ABSTRACT. Discharge from the male accessory reproductive gland (ARG) by the male grasshopper, Melanoplus sanguinipes (Fabr.), has been studied by assay of a characterized product, a glycoprotein LHPI, and the rate of formation of spermatophores. LHPI is an exclusive long hyaline gland (a prominent ARG tubule type) product whose discharge is symmetrical from the bilaterally paired glands. LHPI forms 65% of a viscous secretion that is discharged concomitantly with the spermatophores. Though low ARG reserves in 5‐day‐old males limit both the number of spermatophores formed and LHPI discharged in copulations ≤6 h, this appears to be the result of shorter copulations. The number of spermarophores formed in 1 h was not impaired by general depletion of ARG protein (by repeated copulations) or by selective depletion of long hyaline gland protein (by unilateral and bilateral long hyaline gland removal), though these manipulations reduced LHPI discharge by 22%, 44% and 100%, respectively. However, 56% of spermatophores formed by males with the long hyaline gland bilaterally ablated failed to uncoil properly. These results indicate LHPI and/or other long hyaline gland proteins may act as lubricants. Unlike spermatophore formation and LHPI discharge, which increased steadily up to 90–120 min then levelled off, transfer of radiolabelled male ejaculate to the spermatheca was very variable. In 90 min copulations, only 1% of the total radioactivity (representing c. 5 μg protein) lost from the ARG complex was transferred to the spermatheca. The importance of male‐derived protein in vitellogenesis is discussed.